Brush holder apparatus, brush assembly, and method

ABSTRACT

Devices and methods of use for brush holder assemblies are disclosed. Brush holder assemblies including a mounting block and a brush holder are disclosed. Also illustrated is a brush holder assembly including a first portion in sliding engagement with a second portion. In some embodiments the brush holder includes a channel, such that at least a portion of the mounting block is disposed within the channel of the brush holder.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 12/191,783, filed on Aug. 14, 2008; which is a continuation ofU.S. patent application Ser. No. 11/535,878, filed on Sep. 27, 2006, nowU.S. Pat. No. 7,417,354; which is a divisional of U.S. patentapplication Ser. No. 11/378,155, filed on Mar. 17, 2006, now U.S. Pat.No. 7,122,935; which is a continuation of U.S. patent application Ser.No. 11/172,315, filed Jun. 30, 2005, now U.S. Pat. No. 7,141,906; whichis a continuation of U.S. patent application Ser. No. 10/322,957, filedDec. 18, 2002, now U.S. Pat. No. 7,034,430; which claims priority toprovisional application 60/342,175, filed Dec. 18, 2001, all of whichare incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a brush assembly. More specifically, theinvention relates to a brush holder assembly that may be used inelectrical devices and/or slip ring assemblies.

BACKGROUND

The purpose of a brush in an electrical device is to pass electricalcurrent from a stationary contact to a moving contact surface, or viceversa. Brushes and brush holders are used in electrical devices such aselectrical generators and electrical motors of all sizes. They are alsoused on slip ring assemblies, for example, slip ring assemblies on arotating machine such as a rotating crane. Brushes in many electricaldevices are blocks or other structures made of conductive material, suchas graphite, carbon graphite, electrographite, metal graphite, or thelike, that are adapted for continuous contact with a conductive surfaceto pass electrical current. A brush typically includes one or moreelectrical shunts or wires to provide an electrical current path fromthe brush to other structure. Typically a brush assembly provides forcontinuing contact between a stationary brush and a moving conductivesurface, or vice versa. Over time, the brush will be reduced in size, orget shorter, for example as the contact surface of the brush wears down.It would be desirable to provide a brush assembly that allows forcontinuing good contact even as the brush wears down, and which enablesquick, safe replacement of brushes.

In many designs, a brush box type brush holder is used to support thebrush during operation. The brush and box are designed such that thebrush can slide within the box to provide for continuing contact betweenthe brush and the conductive surface contacted by the brush. During wearof a brush, fine particles and/or dust can be created, which can collecton nearby surfaces and the inside of the brush box. Such material cancreate deposits of brush material on the inside of the brush box thatcan restrict sliding movement of the brush within the box, which in turncan reduce the quality of the contact between the brush and the contactsurface. It would be desirable to provide a brush assembly that allowsfor a reduction of such restriction in movement of the brush.Additionally, it would be desirable to provide a brush assembly whichdoes not allow current to pass through the box to thereby avoiddetrimental effects, such as electrical erosion of the surfaces of thebox, or collection of deposits on the surface of the box, which canrestrict movement of the brush within the box.

Further, typically such boxes include a back plate which is used toenable a spring to press the brush against a conductive surface. Itwould also be desirable to provide a brush assembly which can functionwithout requiring a back plate.

In some instances a brush may become so worn as to require replacement.In some such cases, for example in power generation, it may be difficultor expensive to stop the motion of the moving conductive surface toreplace the brush. However, removal of the brush while relative motionbetween the brush and the conductive surface is ongoing can create arisk of arcing between the brush and the conductive surface, or cancreate a risk of accidental short circuiting the flow of electricity inother components. It would be desirable to provide a brush assembly thatallows for safe, easy removal and replacement of a worn brush withoutrequiring an adjacent collector ring, commutator or other moving part tobe stopped.

SUMMARY

Some example embodiments relate to a brush holder and brush that can bereadily removed from service without removing attachment hardware suchas nuts or bolts. Additional example embodiments pertain to a brushholder that provides a mechanism for retaining a brush in the holder asthe assembly is removed. In some such embodiments, the brush iscontained within the brush holder assembly during removal, therebyproviding for a more contained system that is easier to deal with andcontrol during removal, thereby reducing the likelihood of accidentalshort circuiting of electrical current flow during a removal process.Additionally, in some such embodiments, the more contained system allowsoperations such as the removal of the brush assembly and/or thereplacement or repair of a brush to be performed in a shorter period oftime and with greater ease.

Other example embodiments relate to a brush holder including areplaceable contact system. Some example embodiments pertain to anassembly for attaching a brush spring while eliminating the need forback plate. Other example embodiments pertain to a brush holder using aninsulation scheme to control the flow of current so that current doesnot pass through the brush box.

Some example embodiments pertain to a locking structure to ensure theholder stays locked in place. Several example locking structures includean over-center spring or tension-loaded device that does not releaseunless a force is applied to overcome the over-center force. Someexample locking structures include a safety tab for interacting across ahinged or pivoting portion of a brush holder to prevent motion of thehinge or pivot unless a safety release device is used to release or movethe safety tab.

Additional embodiments include features to prevent arcing between abrush and a conductive surface during removal of a brush while relativemotion between the brush and the conductive surface continues. Someembodiments include mechanisms that allow for replacement of conductiveand/or tension mechanisms within a brush holder structure when a brushwears out, simplifying the process of maintaining such elements. Somesuch embodiments provide for quick, unobstructed access to the inside ofa brush box included in the assembly for cleaning and maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is drawing showing a perspective view of a brush holder assemblyin accordance with one example embodiment, showing the mounting bracketin an engaged configuration relative to the mount block;

FIG. 2 is a drawing showing a perspective view of the brush holderassembly of FIG. 1, showing the mounting bracket in a disengagedconfiguration relative to the mount block;

FIG. 3 illustrates a perspective view of an example brush and spring foruse with several embodiments;

FIGS. 4A-4B illustrate perspective views of attachment of a springsimilar to that shown in FIG. 3 to an illustrative beam of an examplebrush holder assembly;

FIG. 4C illustrates a perspective view of an illustrative terminalconnecting to an illustrative beam;

FIG. 5 illustrates a perspective view where several elements of theillustrative embodiment have been omitted to highlight conductiveelements as coupled together when an example mounting bracket is in anengaged position relative to a mount block;

FIG. 6 illustrates a perspective view similar to that of FIG. 5 exceptthat the conductive elements are shown including a disconnection betweencertain elements because the mounting bracket is in a disengagedposition relative to the mount block;

FIG. 7 illustrates a perspective view highlighting a small portion ofthe perspective view shown in FIG. 2 including a safety lockingapparatus;

FIGS. 8A-8B illustrate perspective views of a removal apparatus for usewith several embodiments;

FIG. 9 illustrates a perspective view of the interaction between aremoval apparatus similar to that of FIG. 8 with a safety lockingapparatus similar to that of FIG. 7 during a disengagement manipulation;

FIG. 10 illustrates a perspective view of a terminal for use in severalembodiments;

FIG. 11 illustrates a cut-away view of an illustrative brush-catchmechanism used in some embodiments, with the brush-catch mechanismretracted;

FIG. 12 illustrates extension of a brush-catch mechanism similar to thatshown in FIG. 11 to engage a brush;

FIGS. 13A-13C illustrate highly schematic views highlighting theover-center locking mechanism used in several embodiments;

FIG. 14 illustrates a perspective view of a lower mount block for use inseveral embodiments;

FIG. 15A illustrates an upper mount block which can be attached to thelower mount block illustrated in FIG. 14;

FIG. 15B illustrates a partially exploded view of attachment of uppermount block of FIG. 14 to the lower mount block of FIG. 15A, andattachment of lower mount block to a mount base;

FIGS. 16A-16B illustrate perspective views of a upper beam which canmate with a removal tool as in FIG. 8; and

FIGS. 17A-17C illustrate highly schematic views of an alternativeover-center design in which the brush does not tip.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The following detailed description should be read with reference to thefigures, in which like elements in different figures are numbered inlike fashion. The figures, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. In some cases, the figures may be highly diagrammatic innature. Examples of constructions, materials, dimensions, andmanufacturing processes are provided for various elements, but are notintended to limit such elements to particular manufactures. Thoseskilled in the art will recognize that many of the examples providedhave suitable alternatives that may be utilized.

As used herein, the terms “upper portion” and “lower portion” areintended as merely illustrative terms which may provide a frame ofreference for explanations of the drawings and claims. Merely placing anelement “upside-down” does not change the inventive concepts herein.Also as used herein, the term “box” does not refer to a particularstructure or enclosure. As illustrated in several of the Figures, a boxmay include a first side, a second side, and a center portion attachedbetween and at approximately right angles to the first and second sides.Often the term box will refer to a shielding or other piece of materialthat may surround another element on several sides. The term “adjacent”includes relatively close proximity, but does not imply contact betweentwo elements which are adjacent one another.

The following detailed description is believed to describe a number ofdistinct inventions and inventive concepts. Each of the followinginventions is illustrated herein as different aspects of oneillustrative embodiment. The several inventions detailed below may beused in isolation from one another to accomplish a variety of tasks.Their inclusion in an individual example together should not beinterpreted as requiring use of any one invention with any otherinventive concept disclosed herein

FIG. 1 is drawing showing a perspective view of a brush holder assemblyin accordance with one example embodiment, showing a beam 14 in anengaged configuration relative to a lower mount block 16. As usedherein, an engaged configuration is one in which a brush holder assemblyis configured to place a brush such as the brush 12 in contact with aconductive surface 13, such as a surface of a collector ring orcommutator, and conduct current therefrom. A brush box 10 surrounds thebrush 12 on several sides, and is affixed to the beam 14. The box 10includes inner surfaces that are adapted to slidingly engage the outersurfaces of the brush 12, and allow the brush to be biased into contactwith the surface 13 when the beam 14 is in the engaged configurationrelative to a lower mount block 16. The beam 14 is hingedly attached tothe lower mount block 16. In several embodiments, the beam 14 may becompletely removed/separated from the lower mount block 16. For example,the beam 14 may include one or more posts which fit into grooves in thelower mount block 16, the post being part of the beam 14 to create pivotline X.

The beam 14 is also hingedly attached to an upper beam 18. The hingedattachment may be at about pivot line Y. The upper beam 18 couples to anupper mount block 20, forming another hinge corresponding to pivot lineZ. The upper mount block 20 engages the lower mount block 16 as betterseen in FIG. 2. A safety catch 22 is fixed to the beam 14 as well, andextends past pivot line Y to pass alongside the upper beam 18. A portionof the safety catch 22 can engage a ledge 30 which is a part of theupper beam 18. A notch 32 is also part of the upper beam 18. Someillustrative examples of characteristics and methods for using thesafety catch 22 and notch 32 are further noted below in text associatedwith FIGS. 7-9 and 15A-15B.

Also illustrated in FIG. 1 is a brush spring 24, which attaches to thebeam 14, for example as shown in FIGS. 4A-4B. The brush spring 24provides tension to the brush 12, as noted below in FIG. 3, to bias thebrush toward the conductive surface 13, such as the surface of acollector ring or commutator. The inner surfaces of the box 10 thatengage the brush are adapted or configured to allow the brush 12 toslide within the box. One or more brush conductor or shunt 26 provides acurrent path for electrical signal from the brush 12. In someapplications, it may be useful to direct current from the brush 12 toanother location without passing the current through the brush box 10,for example, to reduce electrical erosion of the surfaces of the box 10.As shown, a brush conductor 26 couples to a terminal 28, which isanother portion of a current path provided in several embodiments, asfurther highlighted in FIGS. 5-6.

The various elements noted in FIG. 1 may be constructed of any of avariety of suitable materials. In some embodiments, one or more of thebox 10, beam 14, lower mount block 16, upper beam 18 and upper mountblock 20 may be constructed of a metal such as stainless steel, forexample heat treated stainless steel, to provide high strength,durability, and corrosion resistance. However, other materials,including other metals, non-metals, plastics and/or composites may alsobe used. In some embodiments, different parts may be of differentmaterials having different properties, for example, the box 10 may be anon-conductive, light-weight composite, while the beam 14 and lowermount block 16, which must withstand the greatest forces within thedesign, are made of more durable metals such as high tensile strengthsteel.

Several parts may also include non-conductive or conductive coatings,polishes, anti-corrosive coatings, or coatings such as Teflon or thelike, which may inhibit accumulation of dirt and/or debris, inhibitcorrosion, or provide a smooth or slippery surface. Several parts mayalso include surfaces that have been treated or finishing to inhibitaccumulation of dirt and/or debris, inhibit corrosion, or provide asmooth or slippery surface.

For example, some embodiments may include one or more components orparts that include a surface that is electropolished. Electropolishingis a nonmechanical method of polishing metal surfaces that is actuallythe reverse of electroplating. It is an electro-chemical process thatmechanically restructures the surface of a metal by expelling electronsfrom the exposed surface and causing a smoothing reaction. Surface metalis removed by anodic dissolution. This is achieved by making the objector portion of the brush holder assembly to be polished the anode in anelectrolytic circuit, the cathode being of suitable material, forexample, copper, carbon, or the like. The cathode is typically assembledto mirror the surface of the piece being polished. The electrodepotential of the metal piece is altered, typically within a heatedelectrolyte bath. Suitable electrolytes are used, for example, polishingacids, for example, phosphoric, hydrofluoric, nitric, or sulfuric acids,or the like, or combinations thereof. The anode and cathode aretypically submersed in a plating bath including the electrolytes, and anelectrical current is passed through the system to dissolve materialfrom the surface of the anode, and deposit material onto the cathode.The plating bath may be heated, as is generally known, and agitation ofthe system can be created, for example, through blowing air through thebath.

One aspect to the electropolishing process is the difference in currentdensities across the microscopic surface being treated. The currentdensity is greatest at high points and lowest at the low points. Therate of the electrochemical reaction is directly proportional to thecurrent densities. The increased current density at the raised, or highpoints causes metal to dissolve faster at these points and thus levels,or smoothens, the surface material.

In some embodiments, the process is so refined that removal of materialcan be controlled within the range of about 0.0001 inch to about 0.0005inch. Some surfaces can be obtained that become non-particulatingsurfaces, for example, that are so smooth that at least some particlescannot be entrapped and adhere to the metal surface. Additionally,electropolishing can promote corrosion resistance by removing surfacecontaminants and promoting the formation of a uniform and protectivepassive oxide layer.

Such surface treatments or coatings can be particularly useful whenapplied to or used on the inner surfaces of the brush box 10 that maycome into contact with the surfaces of the brush 12. It is desirablethat the brush 12 is able to slide within the box 10 to be biased intocontact with the surface 13 when the beam 14 is in the engagedconfiguration relative to a lower mount block 16. Such coatings ortreatments may enhance and preserve the ability of the brush to slidewithin the box. For example, if the inner surface of the brush box ispolished, coated, or treated as discussed above, in at least someembodiments, there will be less likelihood that particles and/or dustcan collect on the surfaces on the inside of the brush box and createdeposits that can restrict movement of the brush within the box.Additionally, the polished, coated or treated surfaces may be smootheror more lubricious, and therefore allow for better movement of the brushwithin the box.

In an illustrative use of the embodiments shown in FIG. 1, the lowermount block 16 may be attached to a fixed mount (for example, as shownin FIG. 15B). Referring back to FIG. 1, the mount may be placed closerelative to a moving conductive surface 13 such as the surface of acollector ring of commutator, for example, in uses having a slip ring,in generators, or in an electric motor. The mount may be placed suchthat, when the “engaged” embodiment as shown in FIG. 1 is attached to amount, the brush 12 is forced or biased against a moving conductivesurface 13. In other embodiments, the lower mount block 16 may beaffixed to a moveable mount which then moves with respect to a fixedconductive surface. In still other embodiments, relative motion betweena mount and a conductive surface may include movement of both elements.

The brush spring 24 provides force that pushes the brush 12 toward thebottom edge of the brush box 10 as shown by arrow 11. The force providedby the brush spring 24 may be augmented by other biasing structures insome embodiments, while in other embodiments the brush spring 24 may byitself provide force to the brush 12 without other structure.

The brush 12 is shown extending past the bottom edge of the brush box10. This enables a portion of the brush 12 to be supported by the brushbox 10, while also allowing the brush 12 to engage and contact anadjacent conductive surface 13 without damaging the bottom of the brushbox 10.

FIG. 2 is a drawing showing a perspective view of the brush holderassembly of FIG. 1, showing the beam 14 in a disengaged configuration.Again illustrated is the brush box 10 which houses the brush 12 and isaffixed to the beam 14. In a transition from the engaged configurationof FIG. 1 to the disengaged configuration of FIG. 2, hinging actiontakes place at each pivot line X, Y, and Z. Notably, lines X and Y havemoved with respect to the lower mount block 16. Movement of the bottomof the brush box 10 exposes a groove 38, which may be included to allowa post on beam 14 to slidably fit in the groove 38 to create pivot lineX.

While the brush spring 24 continues to apply force to the brush 12, abrush catch mechanism (not shown in FIG. 2 but an illustrative exampleis detailed in FIGS. 11 and 12) prevents downward movement of the brush12. Also in FIG. 2, the safety catch 22 is disengaged with respect tothe ledge 30 of the upper beam 18, as will be further discussed below.

The movement of the beam 14, safety catch 22 and upper beam 18 alsoexposes several additional aspects. The upper mount block 20 is shown toengage with the lower mount block 16 with a fork 36. The upper mountblock 20 can also be attached to the lower mount block 16 using anysuitable attachment mechanism, such as a bolt or screw, or the like, forexample, as shown and discussed below with reference to FIG. 15B. Inother embodiments the upper mount block 20 and lower mount block 16 canbe fused together or provided as a single piece.

Referring to FIG. 2, a conductor strap 34 is also illustrated, theconductor strap 34 being placed optionally over an insulator 35 whichinsulates the lower mount block 16. The insulator 35 prevents currentpassing via the brush 12 from passing through the lower mount block 16.The conductor strap 34, when the device is “engaged” as shown in FIG. 1,contacts the terminal 28, providing a conductive path from the brush 12through the brush conductor 26, the terminal 28 and finally theconductor strap 34. The conductive path thus avoids the brush box 10 aswell as the beam 14, lower mount block 16, upper mount block 20, andupper beam 18.

To further control current passage, various elements including inparticular the beam 14 and brush box 10 may in some embodiments beconstructed of or coated with non-conductive materials. Also, in someembodiments, the brush spring 24 may likewise be coated or constructedto prevent current passage.

Actions to disengage the device, changing the configuration from that ofFIG. 1 to that of FIG. 2 may, in several embodiments, include overcomingan over-center force. Such a design can impede unwanted disengagement(the safety catch 22, included in some embodiments, further impedesunwanted disengagement). Some examples of an over-center force conceptare detailed below in FIGS. 13A-13C and 17A-17C.

FIG. 3 illustrates a perspective view of an example brush and spring foruse with several embodiments. The brush spring 24 includes a spring hook50, a tab 52, and a spring coil 54. The brush 12 includes a brush top55. The spring coil 54 is shaped and configured to press against thebrush top 55. The brush conductor 26 extends around the spring coil 54and is adapted to couple with a terminal such as the terminal 28illustrated in FIG. 10. In some embodiments, the brush top 55 mayinclude a coating or dielectric device for preventing current passagethrough the spring coil 54.

FIGS. 4A-4B illustrate perspective views of attachment of a springsimilar to that shown in FIG. 3 to an illustrative beam of an examplebrush holder assembly. FIG. 4A shows a brush spring 24 coupled to a beam14. The spring hook and tab shown in FIG. 3 are hidden beneath a notch57 in the beam 14. The spring is shown in an extended, or partiallyuncoiled configuration, as though engaging a brush, but the brush is notshown so a better view of the spring can be made. FIG. 4A alsoillustrates the hinge pin holes 58, which provide one location for apivot line. In the illustrative example shown, the hinge pin holes 58correspond to pivot line Y shown in FIGS. 1 and 2. The beam 14 includesa brush catch notch 56, which may optionally be included to provide asafety feature further described below with reference to FIGS. 11 and12. Also shown is a terminal catch 106, which may be used in attaching aterminal to the beam 14, as illustrated in FIG. 4C.

The brush is omitted in FIG. 4A, but it can be seen from viewing bothFIG. 3 and FIG. 4A that the brush (FIG. 3) would lie in front of thebeam 14 (FIG. 4A), with the spring coil 54 engaging the brush top 55(FIG. 3), such that the brush 12 (FIG. 3) would extend beyond the bottomend 59 (FIG. 4A) of the beam 14 (FIG. 4A). The spring coil 54 is adaptedto allow for continued pressure against the brush top 55 (FIG. 3) as thebrush 12 (FIG. 3) wears away during use. Thus the spring coil 54 windsin on itself as the brush top (FIG. 3) moves toward the bottom end 59(FIG. 4A) of the beam 14 (FIG. 4A).

The notch 57 is sized and shaped to receive the spring hook (not shown)in order to attach the brush spring 24 to the beam 14. By attaching thebrush spring 24 to the beam 14, there is no need to supply a back plateto the device, as is often used in other brush holders. Such aconstruction allows the spring 24 to bias the brush 12 against aconductive surface 13, and allows the brush to slide up and down withinthe box.

FIG. 4B illustrates a cut-away perspective view of a portion of a beam14 and brush spring 24 corresponding to an opposite side of that shownin FIG. 4A, focusing primarily on the area of notch 57. The brush spring54 extends through the notch 57 in a region corresponding to the springhook 50. The tab 52 extends into an opening 60 on the back side of thebeam 14 to secure the brush spring 24 to the beam 14. Other embodimentsmay utilize other attachment mechanisms. For example, the spring may beprovided with one or more holes replacing and in the same generallocation as the tab, and one or more attachment mechanisms could beplaced through the one or more holes to secure the brush spring 24 tothe beam 14. The attachment mechanism may be any of a variety ofsecuring mechanisms, for example, a rivet, a bolt, a screw, a sheetmetal screw, an adhesive, solder, weld, and/or spot weld, or the like,or other mechanism.

In some embodiments, the attachment mechanism may be an easily removedor detached attachment apparatus, so that the brush spring 24 may bequickly and easily replaced. In other embodiments, the brush spring 24and attachment mechanism may be more permanent, but may be provided suchthat the beam 14 is not damaged in removing the brush spring 24 andattachment mechanism. One example of such an embodiment would be to makethe beam 14 of a material that does not melt or exhibit plasticdeformation until a very high temperature, with the brush spring 24 andattachment mechanism of lower temperature deformation/melting pointmaterials, so that heating in a furnace or by use of a torch could allowready detachment of the brush spring 24 without damaging the beam 14. Instill other embodiments, the brush spring 24 may be permanently attachedto the beam 14, and the beam 14 may be reused only a few times until thebrush spring 24 is no longer satisfactory for use, at which time thebeam 14 with the brush spring 24 may be discarded.

In an alternative embodiment, a brush spring may be provided which,rather than coiling in on itself as the brush spring 24 of FIG. 4A does,will instead extend outward. For example, a spring may be provided toattach to the beam 14 on top of the brush 12, with the spring providedin a compressed state and expanding to push the brush 12 downward. Morethan one spring may be provided on the same device, too.

Also illustrated in FIG. 4B are several box posts 64. In someembodiments, the box posts 64 are provided as a part of the beam 14 toallow for ready attachment to a box such as the brush box 10 shown inFIGS. 1 and 2. The box posts 64 may allow for removal and cleaning orreplacement of a brush box 10 when a new brush 12 is supplied to thebrush holder. In other embodiments, the box posts 64 may includethreading, pinholes or keyways or the like to allow for a securingapparatus such as a bolt, pin or key to be used in securing the brushbox 10. In other embodiments, the box posts, or other such structure, donot allow removal of the brush box. For example, in some embodiments abrush box 10 may be secured to the beam 14 by welding or the like,either with or without the box posts 64.

A pivot pin 62 is also shown in FIG. 4B. The pivot pin 62 may provide apivot line corresponding to pivot X shown in FIGS. 1 and 2. For example,the pivot pin 62 may mate with and slide in a groove 38 as shown inFIGS. 2 and 14. An alignment pin 63 is shown as well. The alignment pin63 serves to align the lower beam to the lower mount, for example, suchthat the upper locking pin 192 of a upper beam (shown in FIG. 16B)aligns with the pin gap 186 in the upper mount block 20 (shown in FIG.15A), as will be discussed in more detail below. The alignment pin 63 isadapted to fit into relief groove 150 shown in FIG. 14.

FIG. 4B illustrates the “channel-like” nature of the example beam 14.The beam 14 is designed so that a lower mount block such as the lowermount block 16 illustrated below in FIG. 14 may be sized and shaped toslide into a channel 68 defined by the beam 14. The channel 68 allowsthe lower mount block 16 (FIG. 14) to have a regular shape, allowing forseveral mount holes 96 (FIG. 14) through a solid portion of the lowermount block 16 (FIG. 14) so that secure attachment of the lower mountblock 16 is readily performed. Such design also saves space. Forexample, the mount holes 96 (FIG. 14) can be provided beneath the brushand brush box which attach to the beam 14, rather than being next to orbehind these items. This allows for closer brush placement or, in otherterms, higher brush density, such that more or additional brush holderscan be installed and higher amperage capacity can be achieved, ifdesired. The compact design also may allow for use of the replaceablebrush holder designs in smaller generators and motors.

FIG. 4C illustrates another aspect of the beam 14, this time focusing onthe removable attachment of a terminal 28 to the beam 14. As shown, theterminal 28 includes a stop tab 104 which can slide into the terminalcatch hole 106. Because a simple stop tab 104 is used to attach theterminal 28, the terminal 28 may be easily removed and replaced wheneverdesired, or whenever a brush, box, spring or other part is replaced. Insome embodiments, the terminal 28 is permanently attached to the brushconductor 26, and therefore, a new terminal is used anytime a new brushis inserted. In other embodiments, the terminal may be releasiblyconnected to the brush conductor 26, and can be replaced without a newbrush, or the brush can be replaced without a new terminal. Because theterminal 28 conducts current, it may be a target for corrosion andaccumulation of debris. Also, because the terminal 28 must securelycontact a brush conductor 26, it may be advantageous to include a newterminal 28 often. Additionally, in some embodiments, portions of thebeam 14 that come in contact with the terminal may be made of, include,or be coated with an insulating material to prevent the flow of currentfrom the terminal to the beam 14. Some examples of insulating materialcan include plastics, such as Teflon, ceramics, and the like, or otherinsulating material.

In other embodiments, the brush conductor 26 (not shown) may include anattachment apparatus which attaches to the beam 14 instead of a separateterminal, with the brush conductor 26 (not shown) also including adesign allowing it to contact and conduct current to/from a conductorstrap (also not shown).

Also illustrated quite clearly in FIG. 4C are two safety catchattachment pins 107, which can be used for attaching a safety catch 22(FIG. 1) to the beam 14. The safety catch attachment pins 107 may be ofany suitable design and material for attaching to safety catch 22 (FIG.1). The safety catch attachment pins 107, while included in someembodiments, may be excluded in others, since several embodiments alsouse an over-center force mechanism to maintain the brush assembly in anengaged configuration.

FIG. 5 illustrates a perspective view where several elements of theillustrative embodiment have been omitted to highlight a conductivepath. Shown are several conductive elements as coupled together when anexample mounting bracket is in an engaged position relative to a mountblock. The conductive path includes a brush 12 which, in use, wouldcontact a conductive surface such as a collector ring or a commutator.From the brush 12, current is conducted through a brush conductor 26 toa terminal 28. The terminal 28 includes a terminal leaf 70 that conductscurrent to a strap leaf 72 of a conductor strap 34. Each element of theconductive path illustrated in FIG. 5 may be made of any of a number ofconductive materials including, for example, brass, copper, or silver,but any other conductive material will suffice.

In some embodiments, the terminal 28 and/or the conductor strap 34 caninclude material or structure adapted or configured to provide aconnecting force between the terminal and the conductor strap 34. Forexample, the terminal 28 and/or the conductor strap 34, or both, caninclude or be made of a spring material that is configured to bias oneor more portions of the terminal 28 and the conductor strap 34 intoelectrical connection with each other when the mounting bracket is in anengaged position relative to a mount block. For example, in theembodiment shown, the terminal 28 includes two leafs 70 that extendoutward from the terminal to provide a generally u-shaped structure. Theconductor strap 34 also includes two leafs 72 that form a generallyu-shaped structure. The leafs 70, or portions thereof, can be made of orinclude a portion of which is a spring material, such as a springpolymer, spring metal, for example spring copper or the like. The leafs70 can be shaped or configured such that at least a portion of the spacebetween the leafs 70 is smaller than the distance between the outersurfaces of the leafs 72 of the conductor strap 34. Due to the shape,and the use of a spring material, when the leafs 70 come into contactwith the leafs 72, the leafs 70 are spread apart slightly to engage theleafs 72. However, due to the spring nature of the leafs 70, they biasthemselves toward the leafs 72 to provide a connecting force between theterminal and the conductor strap 34. It should be understood that inother embodiments, only one leaf 70 could be used, or more than twoleafs 70 could be used, and a similar biasing force can be created. Itshould also be understood that the leafs 72 of the conductor strap 34could also be made of a spring material and be adapted or configured toprovide an outward biasing force against the leafs of the terminal. Inyet other embodiments, the leafs 70 of the terminal could be adapted andconfigured to fit within the leafs 72 of the conductor strap 34, and toprovide an outward biasing force, and/or the leafs 72 of the conductorstrap 34 could be adapted and configured to provide an inward biasingforce.

FIG. 6 illustrates a perspective view similar to that of FIG. 5 exceptthat the conductive elements are shown including a disconnection betweencertain elements because the mounting bracket is in a disengagedposition relative to the mount block. As illustrated, the conductivepath including the brush 12, brush conductor 26, terminal 28, terminalleaf 70, strap leaf 72 and conductor strap 34 is broken. Whendisengaged, the terminal leaf 70 does not contact the strap leaf 72. Bybreaking the conductive path during disengagement, the possibility ofarcing between a brush 12 and a commutator or other moving conductivesurface during removal or replacement of the brush 12 is reduced. Afurther safety concern is the possibility of current conduction orshorting during servicing of the brush and/or brush holder. By allowinga first step current disconnection as shown and further illustratedbelow, the likelihood of current conduction or shorting can be reduced.

In one embodiment, the lock pin 63 (FIG. 4B) forces the beam 14 (FIG.4B) up as soon as disengagement begins. Then, separation of the terminalleaf 70 from the strap leaf 72 occurs before the brush 12 is separatedfrom an adjacent conductive surface. This combination of movementsallows for interruption of current flow before separation between thebrush 12 and an adjacent conductive surface, preventing arcing betweenthe brush 12 and the conductive surface. This step is useful because ithas been found that such arcing can create a fire hazard and, moreoften, can create a pit or deformation on a commutator or collector ringsurface. Any such pit or deformation will be magnified by further use ofthe brush 12 on the surface and can require expensive and difficultrepairs.

FIG. 7 illustrates a perspective view showing a portion of theperspective view of FIG. 2 including a safety locking apparatus. A beam14 is shown with a safety catch 22 attached at a safety catch attachmentpin 107. As shown, part of the safety catch 22 engages a ledge 30 of theupper beam 18 at place A. While both the upper beam 18 and the beam 14will pivot outward when the device is moved to a disengaged position(i.e. a transition from the configuration of FIG. 1 to the configurationof FIG. 2), the beam 14 and safety catch 22 pivot on a greater radius,so that outward movement forces the safety catch 22 against the ledge30, preventing movement. A removal tool such as that illustrated in FIG.8A-8B can include a safety catch release which fits through the notch 78of the safety catch 22, pushing the safety catch 22 away from the upperbeam 18 so that the safety catch 22 is cleared of the ledge 30. Oncecleared of the ledge 30, the safety catch 22 will not impede atransition from engaged to disengaged configurations.

FIGS. 8A-8B illustrate perspective views of a removal apparatus for usewith several embodiments. Referring to FIG. 8A, a removal tool 80includes a handle 82, which may include or be made entirely of aninsulator to prevent conduction of electricity to the hand of a workersent to remove, replace or otherwise service a brush, brush holder,brush spring, brush box, terminal, collector ring, commutator, orconductive surface. While such insulation may be omitted, the likelihoodof debris and/or dust creating additional conductive paths throughout abrush holder is possible, so that an additional insulator in the handle82 may be advisable. Further, such insulation, from the perspective of aworker maintaining the brush holder, may increase confidence.

The removal tool 80 also includes a release tab 84. The release tab 84may be a spring-loaded device which couples with a spring loaded catchpin 92 (FIG. 8B) that, in turn, can couple with a notch as shown, forexample, in FIG. 15B. A safety catch release 86 is also shown, but isbetter viewed in FIG. 8B.

FIG. 8B illustrates another perspective view of the removal tool 80. Therelease tab 84 is connected to a catch pin 92 such that, when therelease tab 84 is pulled, the catch pin 92 is retracted. Lacking a forceon the release tab 84, the catch pin 92 is in a spring-loaded defaultposition, projecting out from the underside of the removal tool 80.

Also illustrated is a safety tab release 86 including a ledge groove 88and a leading edge 90. Referring now to both FIG. 7 and FIG. 8B, theleading edge 90 (FIG. 8B) is sized and configured to slide past theopening of a notch 78 (FIG. 7) on the safety catch 22 (FIG. 7). Theleading edge 90 (FIG. 8B) is aligned with the notch 78 (FIG. 7) by thesliding interaction between the ledge 30 (FIG. 7) and the ledge groove88 (FIG. 8B). As the leading edge 90 (FIG. 8B) is passed toward thesafety catch 22 (FIG. 7) along the surface of the upper beam 18 (FIG.7), the leading edge 90 (FIG. 8B) encounters and passes through thenotch 78 (FIG. 7).

In one embodiment, the leading edge 90 (FIG. 8B) may be shaped orconfigured so that, as the notch 78 (FIG. 7) is entered and passed, thesafety catch 22 (FIG. 7) is forced outward to finally clear the ledge 30(FIG. 7). Alternatively, the notch 78 (FIG. 7) may be configured sothat, as the leading edge 90 (FIG. 8B) passes therethrough, the safetycatch 22 (FIG. 7) is forced outward to clear the ledge 30 (FIG. 7). Forexample, the leading edge 90 (FIG. 8B) and/or the notch 78 (FIG. 7) mayinclude one or more angled or curved surfaces which, when the leadingedge 90 (FIG. 8B) passes the notch 78 (FIG. 7), comes into contact witha surface on the other of the leading edge (FIG. 8B) or notch 78 (FIG.7) and, on further passage, forces the safety catch 22 to bend or curveoutward.

FIG. 9 illustrates a perspective view of the interaction between aremoval apparatus similar to that of FIGS. 8A and B, with a safetylocking apparatus similar to that of FIG. 7 during a disengagementmanipulation. As shown, the ledge groove 88 has engaged the ledge 30(FIG. 7). Meanwhile, the catch pin 92 (FIG. 8B) is engaged with the pinseat 194 (FIG. 16B) of the upper beam 18. Pulling on the release tab 84(for example, pulling with a thumb) can disengage the catch pin 92 fromthe pin seat 194. The safety catch release 86 is engaged with the safetycatch 22, releasing the safety catch 22 from engagement with the ledge30 (not shown) on the upper beam 18.

Also shown in FIG. 9, and relevant to description with respect to FIGS.5 and 6 is a conductive strap 34, which is made of a conductivematerial. The conductive strap 34 overlies an insulator strap 35, whichhelps prevent current from flowing throughout the rest of the device,isolating the current carrying material of the conductive strap 34. Theconductive strap 34 may be shaped as shown in FIGS. 2, 5 and 6.

FIG. 9 also illustrates several mount holes 96. The mount holes 96 maypass over a mount base on which the lower mount block 16 may be mounted.For example, a pair of threaded bolts may pass through the mount holes96, with nuts and/or washers placed on the bolts to secure the lowermount block 16 to a mount base. One example of such an embodiment isshown in FIG. 15B. In other embodiments, a welded, keyed, pinned orother attachment scheme may be used to secure the lower mount block 16to a mount base near a moving conductive surface or in position to moverelative to a conductive surface.

FIG. 10 illustrates a perspective view of a terminal for use in severalembodiments. The terminal 28 includes a conductor receiver 100, stop arm102, stop tab 104, and terminal leaf 70. The terminal 28 may be formedof a conductive material by any suitable process. In an illustrativeexample, a piece of sheet metal such as copper may be cut and bent intothe illustrated shape.

The terminal 28 is adapted to slide into place on a beam 14. Referringto FIG. 4A, the stop arm 102 may be passed over a top portion of thebeam 14 until the stop tab 104 (FIG. 10) reaches the terminal catch 106(FIG. 4A) and slips into place through the terminal catch 106 (FIG. 4A).Once properly in place, the terminal leaf 70 will extend down to a lowerside of the beam 14 as diagrammed in FIGS. 5 and 6. When the device isin an engaged configuration, the terminal leaf 70 contacts theconductive strap 34 (FIG. 9). As a result of the slip-on nature of theterminal 28, it may be replaced as needed, without requiring that thebeam or other parts of the brush holder be discarded. Further, theslip-on or snap-type terminal 28 used in several embodiments does notrequire additional welds or screws for attachment, simplifying bothreplacement and removal of the terminal 28.

The conductor receiver 100 may be sized or otherwise adapted to providegood contact with a brush conductor 26 (FIG. 3). For example, the insidesizing of the conductor receiver 100 may be such as to apply compressionto a brush conductor 26 (FIG. 3). In additional embodiments, a setscrew, compression screw, soldering location, winding post, snap-downpiece, spring, or other apparatus may be included to augment or replacethe conductor receiver 100 and improve or more strongly secure contactwith the brush conductor 26 (FIG. 3).

FIG. 11 illustrates a cut-away view of an illustrative brush-catchmechanism used in some embodiments, with the brush-catch mechanismretracted. As shown, a beam 14 is engaged with respect to a lower mountblock 16. The surface of the beam 14 is shown with lines included tofurther illustrate features including a guide tab 116 and a brush catchnotch 56. A brush box, which would otherwise conceal the brush catchnotch 56, has been cut-away to expose the brush catch mechanisms.

A brush catch 110 is engaged with a brush catch spring 112 in the brushcatch notch 56. A brush release tab 114 is a part of the lower mountblock 16. The brush release tab 114 may be created or attached by anysuitable method. The guide tab 116 is a part of the beam 14 as furtherillustrated, for example, in FIG. 4A. While the beam 14 and the lowermount block 16 are in the engaged configuration (i.e. the configurationshown in FIGS. 1 and 11), the brush release tab 114 presses against thebrush catch 110 to prevent the brush catch 110 from extending above theguide tab 116 and engaging the brush 12.

FIG. 12 illustrates extension of a brush-catch mechanism similar to thatshown in FIG. 11 to engage a brush during retraction of the beam withrespect to the lower mount block. As shown in FIG. 12, the beam 14 andlower block mount 16 have been disengaged (i.e. the configuration shownin FIG. 2). Once disengaged, the beam 14 may be retracted with respectto the lower mount block 16, revealing a groove 38. During theretraction, the brush catch 110 moves away from the brush release tab114, allowing the brush catch spring 112 to press the brush catch 110 toan extended position, so that the upper end 118 of the brush catch 110engages the brush 12, preventing the brush 12 from moving downward. Theguide tab 116 also stops the brush catch 110 at a most-extendedposition, holding the brush catch 110 engaged with the brush 12 until aforce is applied to the brush catch 110 to release the brush 12. Forexample, after withdrawal of the beam 14 with the brush 12, a technicianmay use a screwdriver or other tool to press against the brush catch110, retracting the brush catch 110 and releasing the brush 12.

In other embodiments, other brush catch mechanisms may also be used toprevent the brush 12 from falling out of the bottom of the brush box 10.For example, referring to FIG. 1, the brush conductor 26 may be sizedand shaped so that the top end of the brush 12 cannot pass beyond thebottom of the box 10 when the brush conductor 26 is coupled to theterminal 28. In another example, referring now to FIG. 3, a loopattached to the brush top 55 may pass through the spring coil 54 (theloop may be tied or clipped into place), with the spring coil 54 pushingon the brush 12 until the spring coil 54 reaches the spring hook 50, theloop then holding the brush 12 in place and preventing further movementforward.

FIGS. 13A-13C illustrate highly schematic views highlighting anover-center locking mechanism used in several embodiments. FIG. 13Aillustrates a brush holder including a brush box 10, a lower mount 130,beam 132, a removal receiver 134, and a groove 136. Hinge locations X,Y, and Z are also shown, hinge X including a pin which may slide withrespect to the lower mount 130 in the groove 136 but which is fixed atone end of the beam 132 (for example, hinge pin 62 shown in FIG. 4B,which may slide in groove 38 shown in FIG. 2). Hinge Y is a hingebetween the beam 132 and the removal receiver 134, while hinge Z is ahinge between the removal receiver 134 and the lower mount 130. Theconfiguration in FIG. 13A is fully disengaged, with the brush box 10tilted and pulled away from the bottom end of the lower mount 130.

FIG. 13B illustrates an intermediate stage of a movement from thedisengaged configuration of FIG. 13A to the engaged configuration shownin FIG. 13C. At this intermediate stage, the slidable hinge X has slidto the end of the groove 136 near the bottom of the lower mount 130. Thehinge Y has not completely straightened out to reach a 180 degreeconfiguration, but both ends of the jointed member including the beam132 and removal receiver 134 are now fixed. Therefore, an additional“over center” force must be applied to force the beam 132 and removalreceiver 134 into the configuration shown in FIG. 13C.

As shown in FIG. 13C, the beam 132 and removal receiver 134 are now in astraight configuration and the device is completely engaged. In thisengagement, there will be tension between stretching forces along thelength of the lower mount 130 applied by the beam 132 and removalreceiver 134 and compressive forces on the beam 132 and removal receiver134 applied by the lower mount 130, due to the over center force notedwith respect to FIG. 13B. In effect, the configuration of FIG. 13C isreached by jamming or forcing the components from the configuration ofFIG. 13B to that of FIG. 13C. This over center force also acts to keepthe pieces engaged as shown in FIG. 13C, and inclusion of a safety latchdevice as illustrated in FIG. 7.

For some embodiments, when the hinge Y is in the configuration as shownin FIG. 13B, the conductive elements of the brush holder may beseparated to prevent current flow, as more completely shown in FIGS. 5and 6. Note that the brush box 10, however, in FIG. 13B, remains nearlyto the bottom of the beam 130 and is in almost the same position as thatshown in FIG. 13C, where the brush holder is engaged and current isflowing. As such, the current may be stopped without a brush in thebrush box 10 being disengaged from an adjacent commutator, preventingcommutator damage due to arcing during removal.

FIG. 14 illustrates a perspective view of a lower mount block for use inseveral embodiments. The lower mount block 16 includes a groove 38 intowhich a pin or pins from a beam may be placed. A relief groove 150 isincluded for the alignment pin 63 of the beam, and can improve thestability and direction of both insertion and withdrawal. For theexample lower mount block 16, the relief groove 150 is more shallow thanthe groove 38, so that, for example, a shorter alignment pin 63 mayengage either groove 38, 150 while a longer primary pin may engage onlythe deeper groove 38. The alignment pin 63 can also serve to align thelower beam to the lower mount, for example, such that the upper lockingpin 192 of a upper beam (shown in FIG. 16B) aligns with the pin gap 186in the upper mount block 20 (shown in FIG. 15A), as will be discussed inmore detail below. A brush release tab 114 is also shown, and mayfunction in accordance with the description of FIGS. 11 and 12. Severalmount holes 96 may include threading or other elements that allow forattachment to a mount base.

The lower mount block 16 may include a fork seat 142 for receiving afork of an upper mount block such as the upper mount block 20 as shownin FIG. 15. The fork seat 142 provides stability to the upper mountblock. The upper mount attachment hole 140 allows for securing the uppermount block to the lower mount block, for example, by welding or byusing a threaded screw or bolt, or other attachment mechanism. The uppermount block is shown in FIG. 15A including a bore for placing a boltinto the attachment hole 140.

The lower mount block 16 may be mounted on any number of surfaces. Ofparticular use may be the fact that lower mount block 16 can be mountedonto a flat surface. This means that the lower mount block 16 can beretrofitted onto existing brush riggings. For example, an existingrigging may include a number of bolts and other elements, which may beremoved and/or cut off of the existing rigging, leaving behind a flatsurface. The lower mount block 16 may then be mounted onto the remainingflat surface by, for example, welding it into place. Alternatively, anyremaining flat surface may be fitted with two bolts, properly placed, towhich the lower mount block 16 may be attached. Because the presentembodiment can be separated into multiple pieces, with the lower mountblock 16 being the only portion that must be “fixed” to a location,attachment steps are simplified, because other parts can be set asideuntil the lower mount block 16 is placed and secured.

FIG. 15A illustrates an upper mount block 20 which can be attached tothe lower mount block illustrated in FIG. 14. The upper mount block 20includes a fork 36 which can enter the fork seat 142 of the lower mountblock 16 shown in FIG. 14. Also illustrated is the counterboredattachment hole 182, which may be aligned with the attachment hole 140of the lower mount block 16 of FIG. 14. An upper locking pin hole 184and pin gap 186 are adapted and shaped to function with upper lockingpin 192 of a upper beam such as that shown in FIG. 16B. The pin gap 186allows complete removal of the upper beam from the upper mount block, asthe upper locking pin 192 (FIGS. 16A and B) is shaped and sized to passthrough the pin gap 186. The alignment pin 63 (FIG. 4B) can engage thegroove 38 and serve to align the lower beam to the lower mount, forexample, such that the upper locking pin 192 of a upper beam (shown inFIGS. 16A and B) aligns with the pin gap 186 in the upper mount block 20(shown in FIG. 15A).

FIG. 15B illustrates an exploded view of how the upper mount block 20 ofFIG. 15A can be attached to the lower mount block 16 of FIG. 14. Athreaded bolt 183, or other such attachment mechanism, can be insertedthrough the attachment hole 182 in the upper mount block 20, and isaligned with and extends into and engages the attachment hole 140 of thelower mount block 16. The attachment hole 140 can include internalthreads that engage the threaded bolt 183, and the bolt can be tighteneddown to connect the upper mount block 20 to the lower mount block 16. Insome embodiments, additional structures 185, such as one or moreBelleville washers, disc springs, or the like, can be disposed about thebolt 183 between the upper mount block 20 and the lower mount block 16to provide a degree of separation force between the upper mount block 20and the lower mount block 16. In some such embodiments, adjustment tothe overall length of the upper mount block 20 and the lower mount block16 when they are connected together can be made. For example, the bolt183 may be loosened such that the structure 185 applies a separationforce between the upper mount block 20 and the lower mount block 16 suchthat the overall length of the upper mount block 20 and the lower mountblock 16 when they are connected is longer. Alternatively, the bolt maybe tightened to compress the structure 185, and thereby shorten theoverall length of the upper mount block 20 and the lower mount block 16when they are connected. Such adjustment may allow for a customized fitwith beam 14 and upper beam 18, and may allow for the adjustment offorce needed to put the mount in an engaged position.

In some other embodiments, additional structures 185, such as one ormore Belleville washers, disc springs, or the like, can be disposedabout the bolt 183 between the upper mount block 20 and the head of thebolt 183 to provide a degree of separation force between the upper mountblock 20 and the bolt head. The bolt can then be tightened down againstthe additional structures 185, such as Belleville washers, disc springs,or the like, such that the additional structures 185 provide apredetermined level of force against the upper mount block 20. In suchembodiments, when the additional “over center” force is applied to forcethe holder into an engaged position (for example, the beam 132 andremoval receiver 134 into the configuration shown in FIG. 13C) thestretching forces along the length of the upper and lower mount blocks16 and 20 and compressive forces on the beam 14 and upper beam 18 can besomewhat absorbed by the additional structures 185. For example, someembodiments may include a stack of Belville washers, for example, in therange of about 1 to 8, or more Belville washers disposed between theupper mount block 20 and the head of the bolt to provide an automatic orcontrolled tensioning force. In some embodiments, the controlled forcecan be in the range of about 100 to about 400 pounds.

FIG. 15B also illustrates one embodiment of how the mount holes 96 maypass over a mount base 41 on which the lower mount block 16 may bemounted. For example, a pair of threaded bolts 43 may pass through themount holes 96, with nuts 45 and/or washers placed on the bolts 43 tosecure the lower mount block 16 to a mount base. As indicated above, inother embodiments, a welded, keyed, pinned or other attachment schememay be used to secure the lower mount block 16 to a mount base near amoving conductive surface or in position to move relative to aconductive surface. The bolts 43, nuts 45, or other such structure mayinclude, be coated with, or be made of an insulative material to helpprevent current passing via the brush 12 from passing through the lowermount block 16.

FIGS. 16A-16B illustrate perspective views of a upper beam which couplesto a removal tool as in FIG. 8. Referring to FIG. 16A, the upper beam 18may include a ledge 30, a hinge pin hole 190, and an upper locking pin192. The hinge pin hole 190 may be included to correspond to pivot lineY illustrated in FIGS. 1 and 2. The pivot line Y therefore pivotsbetween a hinge pin hole 190 of the upper beam 18 and a hinge pin hole58 on the beam 14 shown in FIG. 4A. Ledge 30, as discussed above,performs the function of providing a location for the removal tool ofFIGS. 8A-8B to “grasp” the upper beam 18 as well as providing a locationagainst which the safety catch 22 can press to prevent removal withoutthe proper removal tool.

FIG. 16B provides an additional perspective view of the upper beam 18,again showing the upper locking pin 192, ledge 30 and hinge pin hole190. Also highlighted is a pin seat 194. The pin seat 194 is designed sothat the catch pin 92 of the removal tool 80 shown in FIG. 8B can beinserted therein. Once inserted, the catch pin 92 (FIG. 8B) locks theremoval tool 80 (FIG. 8B) to the upper beam 18 (FIG. 16B), until therelease tab 84 (FIG. 8B) is moved to pull the catch pin 92 (FIG. 8B) outof the pin seat 194 (FIG. 16B).

FIGS. 17A-17C illustrate highly schematic views of an alternativeover-center design in which the brush does not tip. The illustrativeembodiment includes a lower mount 200 on which a brush 202 connected toslide 204 may be mounted. The brush 202 may be slidingly mounted on theslide 204. For example, the slide 204 or the brush 202 may include aspring or other mechanism to push the brush forward against an adjacentcommutator (not shown). A beam 206 connects with slide 204 at hinge T. Aremoval receiver 208 connects with the beam 206 at hinge S. The removalreceiver 208 may be adapted to receive a handle or removal tool such asthe removal tool shown in FIGS. 8A-8B. The removal receiver in turnconnects to a rear mount 210 at hinge R. The rear mount 210 and mount200 may be provided as a single piece, or may be several pieces affixedor joined together. In some embodiments, the hinge R may be a removablehinge or may be adapted to decouple, so that the removal receiver 208can be disconnected from rear mount 210.

FIG. 17A illustrates the example embodiment in a disengagedconfiguration. In use, the mount 200 would be near or adjacent to aconductive surface (not shown), and there may be relative movementbetween the bottom mount 200 and the conductive surface (not shown). Themount 200 is illustrated as including coupling catch 212, which isshaped to receive the bottom of the beam 206 at hinge T.

In FIG. 17B, the angle at hinge S has changed so that the bottom of thebeam 206 now encounters the coupling catch 212. The slide 204 may slidepast the coupling catch, or two coupling catches 212 may be provided,one on each side of the slide 204. As shown in FIG. 17B, the beam 206and removal receiver 208 are mechanically at a point where neither endcan move farther away from the other. In order to reach the fullyengaged configuration of FIG. 17C, an over-center force must again beapplied to force the device into the final configuration of FIG. 17C.

From FIG. 17B to FIG. 17C, the bottom of the beam 206 at hinge T cannotmove forward so the slide 204 does not move, and, therefore, the brush202 remains in the same location. During a removal step, therefore, thebrush 202 would remain engaged with an adjacent conductive surface,while hinge S would be moved from a first, nearly straight, angle, tothe lesser angle of FIG. 17B. This would again allow disengagement ofthe conductive circuit within the brush holder before the brush 202disengages a conductive surface, protecting the conductive surface andbrush 202 from damage due to arcing.

While the above embodiments are often described in terms of removing orreplacing a brush, in some embodiments the primary use of these devicesmay be to allow a maintenance worker to repair, monitor or otherwiseservice a commutator, collector ring, or other conductive surface whicha brush is designed to engage. For example, not only do brushes weardown over time, but commutators engaged by brushes also exhibitdegradation due to wear. It may be useful to easily or reversiblydisengage a brush from a commutator to determine the extent of wear andperform repairs.

Additionally, different embodiments of the invention can be suited andsized for use in the particular electrical device in which they are tobe incorporated. For example, some embodiments are suited and sized foruse in large industrial electrical generators or motors. Someembodiments are particularly well suited and sized for use in powerplants, for example power plants having a capacity in the range of about0.5 to about 900 megawatts, and in some embodiments, power plants havinga capacity in the range of about 300 or greater. It should berecognized, however, that the invention is not limited to use in suchembodiments.

Those skilled in the art will recognize that the present invention maybe manifested in a variety of forms other than the specific embodimentsdescribed and contemplated herein. Accordingly, departures in form anddetail may be made without departing from the scope and spirit of thepresent invention as described in the appended claims.

1. A brush holder assembly for maintaining a brush in contact with aconductive surface, the assembly comprising: a mounting block configuredto extend from a stationary base; a brush holder for holding a brush,the brush holder being removable from the mounting block; a brush forcontacting a moving conductive surface, the brush positionable in thebrush holder; and a spring for biasing the brush into contact with themoving conductive surface, the spring configured to be removablyattached to a structural member of the brush holder without rivets,bolts or screws.
 2. The brush holder assembly of claim 1, wherein thespring includes a retention feature configured to engage with aretention feature of the structural member.
 3. The brush holder assemblyof claim 1, wherein the spring clips to the structural member.
 4. Thebrush holder assembly of claim 3, wherein the spring includes a hole andthe structural member includes a projection extending into the hole. 5.The brush holder assembly of claim 1, wherein the spring includes afirst end portion and a second end portion; wherein the first endportion is a coiled portion configured to press against the brush; andwherein the second end portion includes a hook configured to extendaround an end portion of the structural member of the brush holder. 6.The brush holder assembly of claim 5, wherein the second end portionincludes a tab configured to extend into an opening of the structuralmember.
 7. The brush holder assembly of claim 5, wherein the second endportion includes a hole and the structural member includes a projectionextending into the hole.
 8. The brush holder assembly of claim 5,wherein the structural member is a beam configured to slidably engagethe mounting block.
 9. The brush holder assembly of claim 1, wherein thespring includes a first end portion and a second end portion; whereinthe first end portion is a coiled portion configured to press againstthe brush; and wherein the second end portion includes a hook having afirst portion positionable on a first side of the structural member anda second portion positionable on a second side of the structural member.10. The brush holder assembly of claim 9, wherein the second end portionincludes a projection configured to extend into an opening of thestructural member.
 11. The brush holder assembly of claim 9, wherein thestructural member includes a projection configured to extend into anopening in the second end portion of the spring.
 12. The brush holderassembly of claim 11, wherein the structural member is a beam configuredto slidably engage the mounting block.
 13. The brush holder assembly ofclaim 1, wherein the spring is replaceable without the need of tools.14. A brush holder assembly for maintaining a brush in contact with aconductive surface, the assembly comprising: a brush holder for holdinga brush; a brush for contacting a moving conductive surface, the brushguided by the brush holder; and a spring for biasing the brush intocontact with the moving conductive surface, the spring including a firstportion having a coil configured to press against the brush and a secondportion configured to removably interconnect with and be retained by astructural feature of a structural member of the brush holder.
 15. Thebrush holder assembly of claim 14, wherein the second portion includes ahook portion configured to extend around the structural member of thebrush holder such that a first portion of the hook portion ispositionable on a first side of the structural member and a secondportion of the hook portion is positionable on a second side of thestructural member.
 16. The brush holder assembly of claim 15, whereinthe hook portion includes a retention feature configured to engage withthe structural feature of the structural member.
 17. The brush holderassembly of claim 16, wherein the retention feature of the hook portionis a tab and the structural feature of the structural member is anopening, wherein the tab is configured to extend into the opening. 18.The brush holder assembly of claim 16, wherein the retention feature ofthe hook portion is a hole and the structural feature of the structuralmember is a projection configured to extend into the hole of the hookportion.
 19. The brush holder assembly of claim 14, wherein the springis replaceable without the need of tools.
 20. The brush holder assemblyof claim 14, wherein the spring clips to the structural member.